Playback: Scott Hicks' 'Glass: A Portrait of Philip in Twelve Parts'

The bus driver, normally easy-going in his cowboy boots, is furious. For the past two years, he has faithfully carted my daughter to and from school. I'd arrived at today's pickup with my laptop, planning to grasp a few moments of work before moving into the flurry of homework and dinner.

My daughter is on a nearby bench, slumped low in her hoodie sweatshirt, lacrosse stick by her side. She is the last child here.

My mind shifts to Scott Hicks' documentary Glass: A Portrait of Philip in Twelve Parts. Filmed over 18 months, Hicks follows the renowned composer as his third wife, Holly, cares for their two toddlers. At first, Glass' life appears delightfully glamorous; he travels the world writing symphonies, collaborates with Chuck Close and Errol Morris, crafts scores for Woody Allen.

But the film isn't merely a portrait of a celebrated artist. In an early scene, as he describes his creative process, the viewer hears an off-camera scream and crash. His young son has broken a glass, sending shards everywhere. His wife Holly yells for help. The scene ends with the composer on his knees, piling broken glass into a dustpan.

How do the demands of creativity affect the demands of family? The answer for Glass and his wife is revealed towards the end of Glass. As he obsessively composes a vast opera, she reveals in an interview, "It's hard to live with someone who is writing three scores at the same time."

Her eyes fill with tears. "It worked for a while," she says, an acknowledgement that this is the end.

Suddenly, the door behind Holly bolts open. Glass appears and asks urgently, "What is your computer password?" Holly struggles to refocus her attention. The camera pulls out to reveal the interview microphone dangling above her head. Philip impatiently waits for an answer. Finally Holly slides back into the present. "Frankie," she says wearily. "The password is Frankie."

Glass abruptly shuts the door. Holly sits in silence. Then she looks at the camera.

"Now you all know my computer password," Holly says, and bursts out laughing.

In that single moment, the stress of creative demands, marital tension, external deadlines and household minutiae collide. Hicks allows the moment to unfold in real time. A less experienced director might have cut the scene, or distilled it for a cleaner edit. But messiness is what makes this a haunting and memorable moment.

The bus driver is still glowering at me. I am tempted to explain myself: hundreds of hours I've clocked recently in airports and hotels, half-packed equipment on my office floor, my husband at home supervising homework and sewing a Whoopie Cushion Halloween costume for one of our kids.

In the end, I say nothing. I failed to pick my daughter up on time. Some days, there's no getting the home and work balance right.

The documentary Glass: A Portrait of Philip in Twelve Parts does that rare thing: It explores the tension between the creative process and the demands of family and real life-a tension that too often lets down real good people, sometimes even the ones we love most.

Cynthia Wade is a director/producer whose films have won awards at more than 40 festivals worldwide and have shown on HBO, Cinemax, IFC Channel, the Sundance Channel and PBS. She is currently directing a new feature-length documentary in Indonesia and is also producing the fiction film adaptation of her Oscar-winning documentary Freeheld, directed by Pete Sollett and starring Ellen Page.